Preserving the summer harvest

If all went well with your garden this year, you should be up to your ears in zucchini, tomatoes and other wonderful vegetables and fruits of the summer. Instead of trying to give them away or find yet another recipe for squash, why not try preserving the bounty?

Master Food Preserver Sue Mosbacher told the Our Garden audience this week about different ways to preserve, from traditional canning to dehydrating and freezing. Here are her tips:

Chilling the harvest

Many fruits and vegetables can be stored in the freezer, but take care that your freezer maintains a constant temperature. Allowing food to slightly thaw and then refreeze causes ice crystals to form and reform, making the food mushy.

Produce needs a pocket of cold air around the container in order to completely freeze. Don't pack your food into the freezer during this initial stage. Once the food is frozen, then you can rearrange things to get things tightly packed in.

When adding a lot of food to the freezer at once, turn the temperature down until the food is frozen, then you can return it to its normal setting.

When freezing soft, sensitive foods, such as berries, lay them out in a pan and freeze them individually first. Then you can put them in bags or jars. This prevents the food from clumping together and makes it easier to separate.

It's important to remove as much exterior moisture as possible. Use a hair dryer on a low setting to help remove the water before freezing.

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Food can be stored in glass jars, plastic containers or plastic bags, but make sure they are suitable for the cold temperatures.

Jars should be tempered glass, and containers and bags should be freezer-ready. Regular sandwich bags will allow air in and cause ice crystals to form; freezer bags are less likely.

If freezing liquids, or foods that have a lot of liquid, use straight-necked jars. Jars with shoulders can break as the food hardens and expands.

Getting the air out of containers is important. If you don't have a vacuum sealer, you can use a straw in a baggie. Seal the baggie around the straw, then suck out as much air as you can.

Drying adventures

Dehydrating is a very old way of preserving food, but it has gotten new life in recent years with dehydrators.

The key to successful dehydration is to remove as much moisture in the process as possible, leaving about 20 percent in fruits and 10 percent in vegetables. Food that isn't completely dried can mold or grow other pathogens.

Drying herbs is simple and don't require a machine. You can pick the herbs, put them in a paper bag that has some air slits cut in the side, and then hang up in your kitchen or else where.

There's more than one way to preserve the summer bounty. Dehydrating is a fun technique to explore. (Joan Morris/Contra Costa Times)

The herbs will dry in a few days. Store them in jars or bags, leaving the herb buds whole. When you go to use them, cutting or crushing them will release the flavorful oils.

If drying anything that might have insects or larvae in them, put them in the freezer for 48 to kill any living creatures.

Dehydrators need to reach a temperature of 140 degrees. Good hydrators will have a heater and a fan.

If your dehydrator has the heater on the top, you will need to rotate the trays to make sure the food on the top doesn't dry too much while the food on the bottom doesn't dry enough.

To solve that problem, you can get a dehydrator with the heater on the back.

Be sure to use a timer. Leaving food in the dehydrator too long can over dry it, while not leaving it on enough can lead to mold while in storage.

When making fruit leather -- a puree of fruit that is dried -- try to keep the thickness consistent and uniform to promote even drying.

Leather should be flipped half way through the process.

Fruit leathers can be rolled and stored in plastic bags.

When drying fruit, keep slices uniform.

Be sure to label everything and include a "use by" date.

When storing dried fruit in jars, use jars that have shoulders. If the food still has too much moisture in it, you'll be able to see condensation on the shoulders. If so, just pop the food back into the dehydrator.

Before drying vegetables, blanch them and then put them in a cold bath. To determine the blanch time, add the vegetables when the water is boiling, then take them out when the water starts to boil again.

Be sure to dry off the food as best you can before putting it in the dehydrator.

Fruit such as grapes have a protective skin on them that needs to be perforated before dehydrating. You can cut each one by hand, or blanch them.

Beans are best dried on the vine.

Canning

Two types of canning systems are used to preserve food: water bath and pressure canning.

Foods high in acid can be canned in a water bath; if attempting to can low acid foods, you'll need to add acid, typically in the form of vinegar.

Low acid foods can be canned by pressure canning without having to add acid.

In water bath canning, closed jars of food are put in a bath of boiling water. The jars need to be completely surrounded by water, which requires a rack of some sort to keep them off the bottom of the pan. The pot needs to be deep enough so that the water will cover the tops of the jars.

Use newer recipes for your canned food. Things have changed since our grandmothers' days, making old recipes unreliable. For example, Mosbacher says, the acidity of vinegar is now about 5 percent, but decades ago it was as high as 15 percent.

After the water bath is completed, let jars sit undisturbed on a towel for 12 to 24 hours to ensure the lids are firmly sealed and the air has escaped.

In pressure canning, you need a pressure canner, not a pressure cooker. The canner is specially designed for canning while the cooker is not.

Follow directions and recipes for best results.

Our Garden

Our Garden offers free gardening classes 10 a.m. to 11 a.m. every Wednesday, through October. The garden is located at Wiget Lane and Shadelands Drive in Walnut Creek. Master Gardeners are available to answer your questions and diagnose disease and pests, and there is a wide variety of plants for sale.

Next time in the Garden: Garden myths with Kathy Echols, retired DVC horticulture instructor.